Dame Helen scooped the gong for best actress in a movie or mini-series for her performance in the biopic Phil Spector, at the awards show in Los Angeles. And Downton Abbey's Dame Maggie won the accolade for best actress in a drama series.

The main event saw David O Russell's American Hustle win the top honour - award for outstanding cast, beating 12 Years A Slave, Dallas Buyers Club, August: Osage County and Lee Daniels' The Butler.

Because actors make up the largest branch of the Academy of Motion Picture Arts and Sciences, the SAG Awards are considered one of the most predictive tea leaves of the Oscars.

The awards were a somewhat low-key affair with a few memorable speeches but no earthquakes in a rapidly solidifying award season. The acting winners - Matthew McConaughey (Dallas Buyers Club), Cate Blanchett (Blue Jasmine), Lupita Nyong'o (12 Years A Slave) and Jared Leto (Dallas Buyers Club) - are each probable favourites of their categories.

"It really shines a great light on this bull ride we call acting," said McConaughey, honoured for lead actor in the Texas HIV drama.

"I've been able to recently find some characters that I can humble myself to their humanities and get feverishly drunk on their obsessions."

Coming two days after Academy Award nominations, the SAG Awards are particularly monitored for predicting Oscar momentum. The outstanding cast category, the night's top honour, was perhaps a showdown between American Hustle and 12 Years A Slave. The two very different films were kept separated by drama and comedy categories at the Golden Globes.

Nyong'o won for supporting actress for her performance as the singular slave Patsy in Steve McQueen's historical drama. She thanked McQueen "for taking a flashlight and shining it underneath the floorboards of this nation and reminding us what it is we stand on".

The Kenyan actress, who has been hailed for her red-carpet grace this awards season, recalled her celebratory phone call to her father when she got the part - her first feature film.

"'Daddy, do you know who Brad Pitt is? I'm going to be in a movie with him!'" recalled Nyong'o. "And he said, 'I don't know him personally, but I'm glad you got a job'."

Leto was honoured for supporting actor for playing the gaunt transsexual Rayon, alongside McConaughey's Texas cowboy. He dedicated the award to those who have died of Aids and to "the Rayons of the world".

The Breaking Bad victory lap continued as the show took gongs for outstanding dramatic cast and for lead actor Bryan Cranston.

For his indelible performance as teacher-turned-meth dealer, Cranston added his second lead actor SAG Award, to go with his recent Golden Globe win and his numerous Emmys.

"We have the nicest bunch of white supremacist Nazis I have ever worked with," he said, looking over his former cast-mates. "I swear to you I would kill you all over again."

Michael Douglas won an award for his role in HBO's Liberace drama Behind The Candelabra.

"I am not here without Matt Damon," said Douglas, after making a gay sex pun that made his co-star wince.

Julia Louis-Dreyfus has been a mainstay at award shows recently, both for her acclaimed HBO series Veep (for which she won an Emmy) and the romantic comedy Enough Said (for which she was nominated for a Golden Globe).

She won a SAG trophy for female actor in a comedy series for Veep and slyly mocked the award season crush by first thanking the Hollywood Foreign Press and then the Academy of Motion Picture Arts & Sciences.

"It's hard you know because it's awards season and things get confusing, much like elections," said Louis-Dreyfus. It is the sixth SAG Award for the former Seinfeld star, whose Enough Said co-star James Gandolfini was nominated posthumously for his supporting performance.

The ABC sitcom Modern Family enjoyed another round of awards, winning for ensemble in a comedy series and taking the male actor in a comedy series honour for Ty Burrell.

SAG and the academy do not always agree though: neither August: Osage County nor The Butler was nominated for best picture and The Butler was snubbed entirely.

The effects-heavy, sparsely-peopled Gravity was predictably overlooked by SAG (except for a best actress nomination to Sandra Bullock), while it garnered 10 Oscar nods.

The SAG Awards are one of the more collegial stops on the awards circuit, with winners almost uniformly express gratitude for an honour chosen by their peers. A good speech can help stoke Oscar support.

Emma Thompson, a surprise snub in Thursday's Oscar nominations for the Mary Poppins making-of tale Saving Mr Banks, was just as much the witty, winning award-show attendee she had been all season.

As a presenter, the lead actress nominee noted the show's cheesy lift music soundtrack, saying: "Is this music available on CD?"

SAG's lifetime achievement award was given to Rita Moreno, the 81-year-old West Side Story actress whose career has spanned Broadway, television and music. Introduced by Morgan Freeman, the much-honoured Latina legend danced to the podium before a standing ovation and let out a gleeful expletive.

"I hope the man with the button was there," she said. He was.

Moreno serenaded the SAG audience with a few bars from This Is All I Ask: "And let the music play/ As long as there's a song to sing/ And I will stay younger than spring."